460b0d33cf
Commit under Fixes optimized the number of recv() calls
needed during RTM_GETROUTE dumps, but we got multiple
reports of applications hanging on recv() calls.
Applications expect that a route dump will be terminated
with a recv() reading an individual NLM_DONE message.
Coalescing NLM_DONE is perfectly legal in netlink,
but even tho reporters fixed the code in respective
projects, chances are it will take time for those
applications to get updated. So revert to old behavior
(for now)?
Old kernel (5.19):
$ ./cli.py --dbg-small-recv 4096 --spec netlink/specs/rt_route.yaml \
--dump getroute --json '{"rtm-family": 2}'
Recv: read 692 bytes, 11 messages
nl_len = 68 (52) nl_flags = 0x22 nl_type = 24
...
nl_len = 60 (44) nl_flags = 0x22 nl_type = 24
Recv: read 20 bytes, 1 messages
nl_len = 20 (4) nl_flags = 0x2 nl_type = 3
Before (6.9-rc2):
$ ./cli.py --dbg-small-recv 4096 --spec netlink/specs/rt_route.yaml \
--dump getroute --json '{"rtm-family": 2}'
Recv: read 712 bytes, 12 messages
nl_len = 68 (52) nl_flags = 0x22 nl_type = 24
...
nl_len = 60 (44) nl_flags = 0x22 nl_type = 24
nl_len = 20 (4) nl_flags = 0x2 nl_type = 3
After:
$ ./cli.py --dbg-small-recv 4096 --spec netlink/specs/rt_route.yaml \
--dump getroute --json '{"rtm-family": 2}'
Recv: read 692 bytes, 11 messages
nl_len = 68 (52) nl_flags = 0x22 nl_type = 24
...
nl_len = 60 (44) nl_flags = 0x22 nl_type = 24
Recv: read 20 bytes, 1 messages
nl_len = 20 (4) nl_flags = 0x2 nl_type = 3
Reported-by: Stefano Brivio <sbrivio@redhat.com>
Link: https://lore.kernel.org/all/20240315124808.033ff58d@elisabeth
Reported-by: Ilya Maximets <i.maximets@ovn.org>
Link: https://lore.kernel.org/all/02b50aae-f0e9-47a4-8365-a977a85975d3@ovn.org
Fixes:
|
||
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.